Here's a review... I have some experience with these types of batteries, as my company uses them in some of the UPS Systems we produce for the military. We just touched on this over at the "Hybrid Hatred" thread, but here again is some of the application note I wrote for my company's UPS Systems re traditional sealed lead acid batteries vs. LiFePO4 (full text here http://www.novaelectric.com/life.php
Some advantages of the LiFePO4 are listed below for reference:
4X higher energy density than lead-acid battery: The gravimetric energy density of the LiFePO4 battery is ~130 Wh/kg, almost four times higher than that of a typical Lead-acid battery, at 35Wh/kg. For the UPS user, this means far greater run times while running on battery, without any space penalty.
Light Weight: Despite the vastly higher energy density, the LiFePO4 battery packs are, in most cases, only 1/3 the weight of conventional lead acid packs. So for applications where weight savings are critical, the use of LiFePO4 batteries can result in significant reductions in overall system weight.
Long Life: LiFePO4 battery packs typically achieve a minimum of 2000 cycles with 70% capacity remaining, with up to 5000 cycle potential. This is equivalent to the 8-12 year expected life the very best sealed, lead acid batteries offer. Further, LiFePO4 batteries do not suffer from the “memory effect” of some conventional lead acid batteries.
Better Voltage Regulation: Unlike the Lead acid battery, the LiFePO4 battery terminal voltage remains relatively constant during high rate discharge. This equates to much better performance during high rate (short time period) discharges, yielding a much better AH performance during this type of application, typical in UPS systems.
Wide Temp Range: LiFePO4 battery packs are typically sold for operation between -20°C to +60°C, charging between -10°C to +60°C, and storage between -40°C to +70°C. This is equivalent to the ranges that only premium sealed, lead acid batteries offer.
Safety with power: Safety is equivalent to or better than the traditional lead acid type, without the risk of explosion or fire outbreak associated with some other new battery technologies. The LiFePO4 battery has hybrid characteristics: it is as safe as the lead-acid battery and as powerful as the lithium ion battery.
A Greener Battery: The eco-friendly LiFePO4 battery packs are recyclable and non-toxic.
Battery Management: All LiFePO4 Batteries are provided with a Battery Management System (BMS) which protects the battery cells within the Nova LiFePO4 Battery pack. The BMS will protect the cells to be sure they do not go outside of the normal limits of Cell voltage of the minimum discharge voltage of 2.8 V, the working voltage of 3.0 V – 3.3 V, and the maximum charge voltage of 3.6 V. The BMS also provides short circuit protection which prevents high current in the event of an external short circuit.
Now, obviously, you see that the two main advantages here are tremendous power density and lighter weight. The rest is mainly "equivalent to" in order to assuage skeptical customers looking for a catch.
Batteries like this certainly have their place, in applications where large amounts of battery are required and space or weight becomes an issue - think aircraft, or think of the massive traction battery systems in some hybrid cars. The idea there of getting the same capacity in less space and 2/3 less weight is certainly nothing to sneeze at.
But here, we're talking about one battery, in a fixed tray, on a motorcycle which is not in a category where a few pounds this way or that are going to matter. If you save some space in the battery tray, what are you going to do with it? If the bike weighs a few pounds less, are you going to notice?
So bottom line is, the batteries as replacement cells for the bike or car is, for most people, an answer to a question nobody asked.
Further, for much less money, you can buy a truly good battery, such as Enersys (sold as "Odyssey" to consumers, model PC680 for the RT) which will give you 8-10 years on average without issue and more than enough performance in any given motorcycle application.
Bikini girls are great, and I love them as much as anybody else, but a website with NO useful specs (charge / discharge curves, temp range, lifecycle estimates, etc.) is a sad thing for any serious battery consumer.